Dynamical excitation of the tropical Pacific Ocean and ENSO variability by Little Ice Age cooling

Gerald T Rustic; Athanasios Koutavas; Thomas M Marchitto; Braddock K Linsley

doi:10.1126/science.aac9937

Dynamical excitation of the tropical Pacific Ocean and ENSO variability by Little Ice Age cooling

Science. 2015 Dec 18;350(6267):1537-41. doi: 10.1126/science.aac9937. Epub 2015 Dec 3.

Authors

Gerald T Rustic¹, Athanasios Koutavas², Thomas M Marchitto³, Braddock K Linsley⁴

Affiliations

¹ Department of Engineering Science and Physics, College of Staten Island, City University of New York, Staten Island, NY 10314, USA. Doctoral Program in Earth and Environmental Sciences, Graduate Center of the City University of New York, New York, NY 10016, USA. grustic@ldeo.columbia.edu.
² Department of Engineering Science and Physics, College of Staten Island, City University of New York, Staten Island, NY 10314, USA. Doctoral Program in Earth and Environmental Sciences, Graduate Center of the City University of New York, New York, NY 10016, USA. Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA.
³ Department of Geological Sciences and Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA.
⁴ Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA.

PMID: 26634438
DOI: 10.1126/science.aac9937

Abstract

Tropical Pacific Ocean dynamics during the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) are poorly characterized due to a lack of evidence from the eastern equatorial Pacific. We reconstructed sea surface temperature, El Niño-Southern Oscillation (ENSO) activity, and the tropical Pacific zonal gradient for the past millennium from Galápagos ocean sediments. We document a mid-millennium shift (MMS) in ocean-atmosphere circulation around 1500-1650 CE, from a state with dampened ENSO and strong zonal gradient to one with amplified ENSO and weak gradient. The MMS coincided with the deepest LIA cooling and was probably caused by a southward shift of the intertropical convergence zone. The peak of the MCA (900-1150 CE) was a warm period in the eastern Pacific, contradicting the paradigm of a persistent La Niña pattern.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.